1. Field of the Invention
The present invention relates to a semiconductor apparatus and an inspection method thereof as well as an electric device. For example, the present invention relates to a semiconductor apparatus of a surface mounting type, in which a semiconductor chip, such as an LED (Light Emitting Diode) chip, is implemented on an insulated substrate; a method for inspecting such a semiconductor apparatus; and an electric device using such a semiconductor apparatus.
2. Description of the Related Art
Conventionally, semiconductor light emitting diodes include a chip-type LED and a cannonball-type lamp shape LED. Such a chip-type LED, which can be a thin type, is used as a light source of various display panels, backlight of liquid crystal display apparatuses, illumination switches and the like. The chip-type LED can be implemented by adhering it without modification on a printed circuit board.
FIG. 7 is a perspective view describing a chip-type LED, which is disclosed in Reference 1.
A chip-type LED 50 is formed by implementing a light emitting element 4 on an insulated substrate 1 having a pair of electrodes 2 and 3, and by encapsulating the light emitting element 4 with a resin 6.
The insulated substrate 1 is in a shape of a rectangle in a plan view. A front surface electrode 3a for constituting one of the two electrodes, electrode 3, is formed on one of a pair of opposing edges on the surface of the rectangle, and a front surface electrode 2a for constituting the other of the two electrodes, electrode 2, is formed on the other one of the pair of opposing edges thereof. Further, a back surface electrode 3b for constituting one of the two electrodes, electrode 3, is formed on one of a pair of opposing edges on a back surface of the insulated substrate 1, and a back surface electrode 2b for constituting the other of the two electrodes, electrode 2, is formed on the other one of the pair of opposing edges thereof.
A cutout part 1a having a generally semicircular shape in a plan view is formed both on a side surface of one edge side and on a side surface of the other edge side, of the insulated substrate 1. A side surface electrode 3c for connecting the front surface electrode 3a with the back surface electrode 3b is formed on the surface of the cutout part 1a on one edge side. A side surface electrode 2c for connecting the front surface electrode 2a with the back surface electrode 2b is formed on the surface of the cutout part 1a on the other edge side.
The light emitting element 4 includes an n-side element electrode and a p-side element electrode formed on the bottom surface and the upper surface thereof respectively. The element electrode on the bottom surface side of the light emitting element 4 is adhered to the front surface electrode 2a of the insulated substrate 1 using silver paste 4a. The element electrode on the upper surface side of the light emitting element 4 is connected to the front surface electrode 3a of the insulated substrate 1 using a bonding wire 5.
The surface electrodes 2a and 3a are formed on the front surface of the insulated substrate 1 in such a manner to cover the cutout part 1a, and the back surface electrodes 2b and 3b are also formed on the back surface of the insulated substrate 1 in such a manner to cover the cutout part 1a. A resin 7 is filled in a region in between the front surface electrode 2a and the back surface electrode 2b of the cutout part 1a, and the resin 7 is also filled in a region in between the front surface electrode 3a and the back surface electrode 3b of the cutout part 1a. 
In the chip-type LED 50 with such a structure, each of the upper part sides of the cutout parts 1a formed on the side surfaces of the insulated substrate 1 is covered with the front surface electrode 2a or 3a, so that an encapsulating resin 6 will not get into the region of the cutout part 1a. 
Further, by the filling of the resin 7 into the cutout part 1a, the front surface electrode 3a is reinforced by the resin 7. Owing to this, the front surface electrode 3a will not be deformed even if the bonding wire 5 is bonded in the region above the cutout part 1a of the front surface electrode 3a. 
In the chip-type LED 50 as disclosed in Reference 1, both of the substrate electrode 3, connected with an element electrode of one of the polarities of the light emitting element 4, and the substrate electrode 2, connected to an element electrode of the other one of the polarities of the light emitting element 4, have a structure in which the front surface electrode and the back surface electrode are electrically connected with each other through a side surface electrode formed in the cutout part 1a on the side surface of the insulated substrate 1. Therefore, there is a problem of disconnection or bad connection occurring at a connection part between the side surface electrode formed in the cutout part 1a and the front surface electrode or back surface electrode, due to deterioration over time, thus causing the malfunction, or deterioration in the characteristics, of the LED 50.
Thus, among chip-type LEDs, such LEDs have been developed where electrodes of respective polarities formed on an insulated substrate are structured to have a plurality of side surface electrodes in cutout parts 1a for connecting front surface electrodes and back surface electrodes.
FIG. 8 is a perspective view describing an improved conventional chip-type LED. FIG. 9 is a plan view describing an improved conventional chip-type LED, illustrating the one cut out into a chip as a structure of a back surface electrode of the chip-type LED (FIG. 9(a)) and the one before being cut out into a chip (FIG. 9(b)).
A chip-type LED (light emitting apparatus) 200 includes a light emitting element Ed, which is implemented on a ceramic substrate 201 in a shape of a rectangle in a plan view, and which is encapsulated with resin (not shown). A cathode electrode (not shown) of the light emitting element is connected to a front surface side cathode electrode 203 of the ceramic substrate 201 with a bonding wire W, and an anode electrode (now shown) of the light emitting electrode is connected to a front surface side anode electrode 204 of the ceramic substrate 201 with a bonding wire W.
The front surface side cathode electrode 203 is connected to a cathode electrode 205 on aback surface side of the ceramic substrate 201 via two side surface electrodes 205a and 205b, the side surface electrodes 205a and 205b being formed on the front surface of cutout parts (a part A in FIG. 8) having a generally semicircular shape in a plan view on a side surface of the ceramic substrate 201. Similarly, the front surface side anode electrode 204 is connected to an anode electrode 206 on the back surface side of the ceramic substrate 201 via two side surface electrodes 206a and 206b, the side surface electrodes 206a and 206b being formed on the front surface of cutout parts having a generally semicircular shape in a plan view on a side surface of the ceramic substrate 201.
FIG. 9(b) is a diagram illustrating a state where a chip-type LED (light emitting apparatus) 200 is formed in each of chip regions Rc of one base substrate, and where the base substrate is viewed from the back surface side thereof.
Scribe grooves SLv in a longitudinal direction and scribe grooves SLh in a transverse direction are formed on the back surface of a base substrate B, and a region (chip region) Rc surrounded by the scribe grooves includes a structure formed therein, which will be cut out as a light emitting apparatus 200.
In the chip region Rc, the cathode electrode 205 and the anode electrode 206 are formed along the scribe grooves SLh in a transverse direction. Two through holes TH are formed in the scribe groove SLh between a pair of chip regions Rc adjacent to each other in the longitudinal direction, and a conductor layer is formed on an internal surface of the through hole TH, which will be a side surface electrode of the ceramic substrate when being cut out into a chip. In addition, the upper part of the through hole TH is buried with an insulation member, such as a glass layer, or a dry film, in order to prevent encapsulating resin (not shown) from entering the through hole TH.
Similarly to the back surface side, another cathode electrode 203 and another anode electrode 204 are formed in each chip region on the front surface side of one base substrate.
In the chip-type LED 200 with such an improved structure, the front surface electrode and the back surface electrode of the insulated substrate are connected with each other through the side surface electrodes 205a and 205b or side surface electrodes 206a and 206b inside the two cutout parts formed in the insulated substrate. Thus, even if a bad connection, for example, occurs between the side surface electrode inside one cutout part and the front surface electrode or back surface electrode of the insulated substrate, the front surface electrode and the back surface electrode of the insulated substrate are electrically connected with each other through the side surface electrode of the other cutout part. As a result, a bad electrical connection will not occur between the front surface electrode and the back surface electrode, which makes it possible to prevent a back connection from occurring due to deterioration over time.
Next, a method for forming an electrode in an insulated substrate of such a chip-type ED 200 will be briefly described.
FIG. 10 is a diagram describing a forming process of an electrode of an improved conventional chip-type LED.
First, a printed conductor layer is formed as a front surface electrode 203, on a front surface of a ceramic substrate 201 in which through holes TH are formed (FIG. 10(a)). Next, a printed conductor layer is formed as a side surface electrode 205a on an internal surface of the through hole TH in such a manner to be connected with the front surface electrode (FIG. 10(b)). Subsequently, a printed conductor layer is formed as a back surface electrode 205 on a back surface of the insulated substrate 201 in such a manner to be connected with the side surface electrode (FIG. 10(c)). Subsequently, the ceramic substrate 201 is baked to solidify the ceramic substrate 201 (FIG. 10(d)). After the baking of the ceramic substrate 201, an insulation layer (not shown), such as a glass layer or a dry film, is formed in such a manner to cover the upper part of the through hole TH.    Reference 1: Japanese Laid-Open Publication No. 2001-177159